ABET's outcomes-based assessment and evaluation requirements for engineering school accreditation has been a catalyst for curricular reform for engineering programs across the U.S. and around the world. Norfolk State University launched programs in Electronics and Optical Engineering in 2003. In 2007, Norfolk State became one of only six accredited Optical Engineering programs in the United States. In preparation for their first ABET evaluation in fall 2007, the faculty initiated an embedded-assessment program to insure continuous improvement toward the desired learning outcomes. The initial program design includes embedded assessments that have been generated using a practical framework for the creation of course activities based on Bloom's Learning Taxonomy. The framework includes specific performance criteria for each ABET-defined learning outcome. The embedded assessments are generated by individual faculty for courses that they are assigned to teach, and the performance criteria provide sufficient information to guide the faculty as they generate the embedded assignments. The assignments are typically administered through course exams, projects, electronic portfolio assignments, and other structured educational activities. The effectiveness of the assessment design is being evaluated through faculty surveys, faculty group discussions, and student performance. This paper outlines the assessment and evaluation plan, and the integrated processes that have been used to support the evaluation of learning outcomes using embedded assessment instruments.
Light output degradation of nonhermetic packaged AlGaAs LEDs has been characterized, following application of accelerated stress testing of the LED component. Our data have been applied to a previously reported 'Black Box' acceleration model, to determine the model coefficients for temperature, ambient humidity and current biase of the LED device. The stress testmparameters included 3 levels of moisture, between 55% and 100%, 3 elevated temperature levels between 35 degrees Celsius and 121 degrees Celsius, and 3 current bias conditions between 0mA and 40mA. Where device failure has not occurred during the test period, the time to failure (TTF) for an individual part has been projected to the time at which 50% reduction in the light output power will occur. The TTF data was then fit to a lognormal distribution to obtain the mean time to failure (MTTF) for each stress level of the study. The dependence of MTTF on temperature and relative humidity is assumed to be, C0(DOT)exp[Ea/KT](DOT)exp[-Arh(RH)2]. The activation energy (Ea), and relative humidity coefficient (Arh) were determined from our accelerated test data. Our results show different behavior when testing with no in-test current bias, indicating a different physical mechanism for degradation under these conditions. Finally, physical analysis of aged devices point to a moisture drive corrosion mechanism, leading to eventual failure of the LED.
In-fiber Bragg grating sensors have been used to study mechanical strain in optical fibers that have been terminated in ST connectors. Our findings indicate that terminated sensors experience a compressive strain whose magnitude depends on the cure profile of the epoxy encapsulant used in these connectors. These experiments demonstrate the viability of using in-fiber sensors to characterize fiber optic connector assemblies during and following termination. However, the stain state of the sensing environment is a complex one, so there is the challenge of reading out the correct strain from the sensor response. To address this problem, the T-matrix formalism is being utilized. A review of this method and examples of its use will also be presented.
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